An extremely desirable characteristics of a denture fixative composition is that it quickly generates tacky, uniform and viscous mucilages upon contact with saliva. It is also highly desirable that the mucilages spread over the denture-mucosa interface in order to effectively seal the denture in place and that the mucilages possess sufficient cohesive strength to withstand the stresses of mastication which act to rupture the seal and thus dislodge the denture.
U.S. Pat. No. 3,003,988 describes a dental fixative composition in which the dental fixative is a mixed partial salt containing calcium cations and alkali or quaternary ammonium cations of a lower alkyl vinyl ether-maleic anhydride type copolymer. The mixed salt copolymer is described as a water insoluble but water sensitized copolymer.
U.S. Pat. No. 3,736,274 teaches a dental fixative composition which contains a lower alkyl vinyl ether maleic anhydride polymeric material, a polymeric N-vinyl lactam and sodium carboxymethylcellulose. The carboxymethylcellulose prevents the maleic anhydride copolymer N-vinyl lactam complex from completely precipitating when placed in water.
U.S. Pat. No. 3,868,432 teaches an anhydrous denture adhesive composition which is a mixture of a cationic polymeric component which is a copolymer of an acrylamide and an anionic synthetic gum component which can be a copolymer of maleic acid with vinyl lower alkyl ether.
It has now been discovered that certain partially neutralized copolymers of alkyl vinyl ethers and maleic acid or anhydride, optionally partially crosslinked, can be employed as a denture fixative when combined with certain hydrophilic polymers. Despite being water soluble, the partly neutralized or partly neutralized and crosslinked copolymers develop, when in contact with saliva, a high degree of tack and a viscous mucilage of high cohesive strength which can be spread over the denture mucosa interface to fill the gaps and thus provide superior fixative properties.
Accordingly, it is the object of this invention to provide new denture fixative compositions in which the fixative is water soluble yet develops a high degree of tack and viscous mucilage of high cohesive strength when contacted with saliva. This and other objects of the invention will become apparent to those skilled in this art from the following detailed description.